The present invention relates to brake pads and linings and pertains particularly to an improved method and composition for making same.
Until recent years, the predominant material used in the manufacture of friction pads and discs for brakes, clutches and the like was asbestos. However, it was discovered that asbestos is a carcinogenic substance, and that such use released potentially harmful amounts of it into the environment. Extensive efforts have been put forth in an effort to find suitable environmentally safe materials having the desirable wear and heat resistant characteristics as asbestos.
Attempts to satisfy the need for long life, high friction heat resistant materials have included proposals to utilize various chopped fibers molded in a bonding matrix, such as a resin. The friction unit is formed by a molding process, with the fibers randomly oriented. However, friction units made by this method are expensive to manufacture and have not been satisfactory.
It is desirable that improved methods and compositions be available for the manufacture of friction units.